Many metal finishing and printed circuit board operations produce large amounts of waste water which contain heavy metals wastes. These wastes are produced as a bi product of the metal finishing and printed circuit board industries which employ acid and caustic solutions to form hydroxides and other complexes. Several methods for disposing of the waste water are used including treating such waste water in conventional filter presses to remove water and concentrate the solids and thereby reduce the bulk of the material. Filter presses often obtain 25 to 30 percent by weight solids in such metal finishing waste waters. Such filter presses are often disposed in frames three feet or so above a working surface and then unloaded after dewatering into troths or bins placed under the filter presses for removal to further processing or disposal areas.
A known filter press as described above is produced by JWI, Inc. of Holland, Mich. under the tradename J PRESS and is suggested for use with dumpsters or drum disposal systems for removal of treated cakes often containing up to 30 percent solids.
Sludge driers have been used in the past but often have limitations as to drying time, capacity, ease of use or the like.